Different scenarios for survival analysis of evolutionary algorithms

Empirical analysis of evolutionary algorithms (EAs) behavior is usually approached by computing relatively simple descriptive statistics like mean fitness and mean number of evaluations to convergence, or more theoretically sound statistical tests for finding significant differences between algorithms. However, these analyses do not consider situations where the EA failed to finish due to numerical errors or excessive computational time. Furthermore, the ability of an EA to continuously make search improvements is usually overlooked. In this paper we propose the use of the theory from survival analysis for empirically investigating the behavior of EAs, even in situations where not all the experiments finish in a reasonable time. We introduce two scenarios for the application of survival analysis in EAs. Survival trees, a machine learning technique adapted to the survival analysis scenario, are applied to automatically identify combinations of EA parameters with similar effect in the behavior of the algorithm.